10.11.1 Controlling the Verbosity of patch

You can cause patch to produce more messages by using the
--verbose option. For example, when you give this option,
the message ‘Hmm...’ indicates that patch is reading text in
the patch file, attempting to determine whether there is a patch in that
text, and if so, what kind of patch it is.

You can inhibit all terminal output from patch, unless an error
occurs, by using the -s, --quiet, or --silent
option.